水头损失计算毕业论文

AbstractThe content of this paperis the city of BeijingDaxing District 70000tons /day of urban sewage treatmentplantpreliminary design,processfor Carlo Saltypeoxidation ditch process,mainly for thedomestic sewagetreatment of to theoriginal datarequirements ofgraduation design,citysewage treatmenteffluent quality to achieve"urbansewage treatment plant pollutantdischarge standard"(GB18918-2002)is a are mainlyphysical treatmentandbiological treatment,mainlyis the physicalprocess,the raw water from thecitypipelineinto the factoryafter theremoval ofpollutantsin thegrille,large,and then by thelift pumpdeliveryto sink sand pool,the removal ofhigh densityinorganicgrit;the latter is mainlythrough theoxidation ditchwastewaterbiochemical treatment,nitrification,denitrification,goodoxygen,anaerobictreatment,achievetheremoval of nitrogen and phosphorus,decreased BOD,COD,make water qualityreach the emission sludgebysludge pumptogravity thickener,canreduce the water content of the sludge,sludge sludgedrying anddehydration treatment,thesludge to thecalculation of the sewageplant layoutprinciple andstructure designresults,do thelayoutof sewage treatment plant,according to the sewageflow,theconstruction ofpipelines,among thedeterminedvelocity,energy loss calculation,goodsewage treatment plant elevation sewage treatment plantof the main structures: thegrille,pump house,setinthe wells,sand pool,Carrousel oxidation ditch,sedimentation tank,ultraviolet disinfectionroom,gravityconcentration tank,dewatering roometc..Keywords:sewage treatment,Carrousel oxidation ditch,citysewage,nitrogen and phosphorus removal

搞本化工原理，里面第一章好像就有所有的水头损失的计算，当然也有高程和提泵房的东西。话说我记得环境工程里面也有啊

单位重量的水或其他液体在流动过程中因克服水流阻力作功而损失的机械能，具有长度因次。水头损失可分为沿程水头损失hf及局部水头损失hj两类。某流段的总水头损失hw为各分段的沿程水头损失与沿程各种局部水头损失的总和 克服沿程摩擦阻力作功而损失的水头，它随着流程长度而增加。恒定均匀管流沿程水头损失的达西－魏斯巴赫公式式中g为重力加速度；d、l、v为管道直径、 流段长度、断面平均流速；λ为无因次系数,称为沿程摩阻系数。式(2)亦适用于明渠水流，式中管径d须代以明渠水力半径R（见谢才公式）的4倍。德国学者J.尼库拉德塞曾用人工砂粒粗糙的办法进行系统试验, 结果绘成以1g(100λ)及lgRe(雷诺数 ，ν为液体运动粘滞系数)为纵横坐标,以相对粗糙度r0/κs(r0为圆管半径,κs为砂粒粗糙高度)为参数的曲线图。图中ɑb线代表层流区， 。c以右为紊流区,又可分为三个流区：①光滑区(cd线), λ=f(Re)；②完全粗糙区(ef线以右的B区)属充分发展了的紊流, , ,又称阻力平方区;③过渡粗糙区(cd、ef线间的A区),λ=f(Re,κs/r0)。b、c之间为层流转变为紊流的过渡区，试验点子乱，范围狭窄，一般可作紊流对待。b点，Re≈2300；c点Re≈4000。明渠均匀流的λ值也有类似的变化规律。水头损失工程界习惯沿用一些经验公式和图表计算沿程水头损失。明渠流实际上多属阻力平方区，广泛采用谢才公式和曼宁公式。 在流动局部地区因边界急局改变引起流动急剧调整、消耗能量而损失的水头。管渠中进水口、弯段、门槽、断面突然扩大或突然收缩，管道中设置阀门、接头或其他配件，常引起流动分离并发生旋涡。旋涡的形成与衰减及流速分布的急剧改变均会消耗液体机械能。高雷诺数下的水流试验表明，局部水头损失近似地与该局部地区的特征流速水头成正比，即：(3)局部水头损失系数ζ的大小基本上取决于流动的几何条件，如断面急剧改变前后的面积比，弯管相对曲率半径，阀门的形状和尺寸等，ζ值由实验测定。低雷诺数流动的ζ值不仅与流动几何条件而且与流动状态(Re值)有关。